100 Short Circuit Current Rating.

[fmtjfw]

Section/Paragraph: 100 Short Circuit Current Rating.

Revised Text

Short-Circuit Current Rating. The prospective symmetrical fault current at a nominal voltage to which an apparatus or system is able to be connected carry without sustaining damage exceeding defined acceptance criteria.

Substantiation:

SCCR is about the ability to "carry" a current, not to be "connected". It is not clear to me what "connected" means in this context.

insert delete

 

[iwire]

Section/Paragraph: 100 Short Circuit Current Rating.

Revised Text

Short-Circuit Current Rating. The prospective symmetrical fault current at a nominal voltage to which an apparatus or system is able to be connected carry without sustaining damage exceeding defined acceptance criteria.

Substantiation:

SCCR is about the ability to "carry" a current, not to be "connected". It is not clear to me what "connected" means in this context.

insert delete

I think it is very clear as it is.

 

[jim dungar]

Your proposal changes the meaning entirely.

"Connected to" is the amount of potential short circuit amps. It is very easy to calculate as all upstream impedances and sources must be considered.

"Carry" means the current flows through it. Now you need to decide how much impedance needs to be considered in order to determine the amount of current. Consider a simple power distribution block: do you use 0 inches of conductor (e.g. the load side lugs) or maybe the 300' of conductor to the next piece of equipment.

Short circuit current rating covers a wide range of situations. It is a standard term used by NRTL and manufacturers.
Withstand rating is a narrower term that defines the ability to carry current, it is primarily used with MV equipment